I was browsing Frequency's website and found this presentation which is dated April 2020:
https://investors.frequencytx.com/static-files/6d161090-16f5-49f4-9606-8caceb5a88a1
One bit of info that caught my eye was that it says: "Phase 2a study ongoing; ~50% enrolled*". That seems kind of low, especially considering that they expect to be done at the end of September [1]. With the study taking 210 days, and there being only ~180 days between March 26th and Sept 30th, I don't see how they can finish on time.
Based on the 50% number, they have 48 people enrolled. I'm not sure sure what number of people is needed for a phase II study, but maybe that's enough people?
[1]
https://clinicaltrials.gov/ct2/show/NCT04120116